1. Field of the Invention
The technical scope of the present invention is that of pipelines for the transportation of very low temperature fluids, and in particular for the transportation of liquefied natural gas under ground, above-ground, or under the sea.
2. Description of the Related Art
Patent FR-2748545 describes a pipeline for the transportation of liquefied natural gas comprising two coaxial pipes. This type of pipeline has thermal insulation properties but also suffers from drawbacks. Indeed, the contraction of the inner pipe (by around 1 m for a pipe of a length of 4,000 m) requires the use of a steel linking part between the two pipes placed before the end of the straight part of the pipeline, such a linking part creating a thermal bridge and resulting in:                a deterioration in the thermal efficiency of the assembly,        a lowering in the temperature of the external pipe, thereby embrittling it and making it sensitive to impacts and concentrations of stress.        
Moreover, the use of a simple external wall cannot be considered sufficient in terms of reliability.